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Open Source C# .NET API for Faster OCR Text Recognition

Free C# .NET Optical Character Recognition (OCR) API for Faster Text Recognition from Images, Including Scanned Documents, Multi-page PDFs, and Photographs.

What is Free-OCR-API-CSharp?

As digital transformation accelerates, the need for accurate and efficient text extraction from images and documents has never been greater. Optical Character Recognition (OCR) has become an essential technology in this space, enabling software to convert printed or handwritten text into machine-readable content. If you're a developer looking for a free .NET OCR API to power your applications, you're in luck. Free-OCR-API-CSharp is a reliable and fully free C# OCR API designed specifically for .NET developers. It provides a hassle-free way to integrate OCR capabilities into your C# applications—no external dependencies, no registration, and absolutely no licensing fees. This makes it an ideal solution for startups, indie developers, and enterprises alike.

What sets this fast OCR API apart is its advanced recognition engine. Whether you're working with scanned documents, photographs, or PDF files, the API delivers fast text recognition with impressive accuracy. It easily handles various font styles and sizes and supports multiple languages including English, French, German, Italian, Portuguese, and Spanish.With Free-OCR-API-CSharp, you get both speed and precision—an essential combination for building modern document processing tools, automation workflows, and data extraction solutions. If you’re looking for a powerful, cost-effective, and easy-to-implement OCR solution, this free .NET OCR API is the smart choice.

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Getting Started with Free-OCR-API-CSharp

The recommend way to install Free-OCR-API-CSharp is using NuGet. Please use the following command for a smooth installation.

Install Free-OCR-API-CSharp via NuGet

 Install-Package Free-OCR-API-CSharp

You can also install it manually; download the latest release files directly from GitHub repository.

Recognize Text from Images via C# OCR API

The open source API Free-OCR-API-CSharp has included support for a great feature for speedy recognizing text from various types of image in various languages inside .NET applications. To achieve the task software developers just need to load their image into a byte array and call the OCR method of the FreeOcrApi instance, passing in the byte array and the language of the text to recognize. The library also provides a great feature for batch recognize text from multiple files at once making it easy to process a lot of files at once. The following example shows how to recognize text from images using C# .NET code.

How to Recognize Text from Images via C# API?

using System;
using System.IO;
using FreeOcrApi;
var ocr = new FreeOcrApi("your-api-key");

// Load your image file into a byte array:
byte[] imageData = File.ReadAllBytes("path-to-your-image-file");
string recognizedText = ocr.OCR(imageData, "eng");

// Finally, display the recognized text in the console or save it to a file:
Console.WriteLine(recognizedText);
File.WriteAllText("path-to-output-file", recognizedText);

Create Searchable PDF File via C# API

The open source API Free-OCR-API-CSharp allows software developers to create searchable PDFs (also known as Sandwich PDFs) directly inside their own C# applications. By default, the added text layer is visible which gives users an great opportunity for testing the result as they can compare the OCR'ed output directly with the scan image. The following example demonstrates how software developers can load an image and convert it into search PDF documents using C# code.

How to Create Searchable PDF via C# ApI?

using System.IO;
using FreeOcrApi;
using PdfSharpCore.Drawing;
using PdfSharpCore.Pdf;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            FreeOcrApiWrapper api = new FreeOcrApiWrapper("YOUR_API_KEY");
            MemoryStream imageStream = new MemoryStream(File.ReadAllBytes("path/to/image.jpg"));
            string text = api.Recognize(imageStream);
            PdfDocument pdf = new PdfDocument();
            PdfPage page = pdf.AddPage();
            XGraphics gfx = XGraphics.FromPdfPage(page);
            XFont font = new XFont("Verdana", 12, XFontStyle.Regular);
            gfx.DrawString(text, font, XBrushes.Black, new XRect(0, 0, page.Width, page.Height), XStringFormats.TopLeft);
            pdf.Save("path/to/output.pdf");
        }
    }
}
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